Consider Adding Traffic Router Config for Certificate Check Interval GH #1780

Currently, when Traffic Router doesn't have certificates for delivery services, it sleeps for a hard-coded 1 second and tries again, infinitely.

See b89c9c8#diff-895918d726d34df684cb81881e1b72f9R137

We should consider making the time interval a config, to allow dynamically changing the time between checks.

We may decide this is too small to be worth another config param. But we should think about it and make a decision.

If it is a config, it should probably be a static value, not exponential backoff, because there's no network activity. This checks a data object which is fetched by another thread, so the cost is only a tiny amount of CPU.